Field of the Invention
The present invention relates to a magnesium material, and more particularly, to a magnesium material having a structure capable of improving ignition and mechanical properties, and a method of manufacturing the same.
Description of Related Art
Mg (magnesium) is an environmental friendly material that has a density of 1.74 g/cm3, which is merely ⅕ of Fe and ⅔ of Al, and generally has superior strength and can be easily recycled. Mg is also evaluated as an ultra-lightweight structural material, and has the specific strength and elastic coefficient of which are comparable to those of other lightweight materials, such as Al alloy. In addition, Mg exhibits a superior ability to absorb vibration, impact, electromagnetic wave and the like, and has superior electrical and thermal conductivities.
However, Mg and Mg alloys (hereinafter, also collectively referred to as magnesium material) have the fundamental problem of poor corrosion resistance despite of the above-mentioned excellent characteristics. Since it is known that Mg rapidly corrodes under electromotive force (EMF) and in a galvanic reaction due to its high reactivity, the use of Mg is limited to internal parts in which corrosion environment conditions are not strict or regions in which strength, thermal resistance and corrosion resistance are not highly required. Therefore, although a technology for fundamentally improving the corrosion resistance of Mg and Mg alloys is still required, this requirement is not satisfied by present technologies.
In the meantime, it has been known a method of forming a coating on a surface of a material so as to improve the corrosion resistance. For example, Korean Patent Application Publication No. 10-2008-66580A discloses a surface treatment method of an aluminum alloy. A coating layer is formed through processes of removing an aluminum oxide film, forming a nickel-plated film, forming an electroless copper plated film, and the like, so that an aluminum matrix is protected.
Also, the Mg material melted at high temperatures, i.e., the molten Mg material is likely to ignite. Usually, when Mg is melted at 640° C., it immediately ignites, and Mg alloys ignite at about 400° C. in many cases. In order to increase the ignition temperature, a protective gas such as SF6 and SO2 is used. However, the protective gas is harmful to a human body and corrodes an equipment, so that the use thereof is strictly limited. Regarding this, Korean Patent Registration No. 10-1045218 discloses a technology of adding an additive such as CaC2, CaCO3 and the like to the molten magnesium so as to reduce a using amount of the protective gas and to improve the ignition property.
The information disclosed in the Background of the Invention section is provided only for enhancement of (or better) understanding of the background of the invention, and should not be taken as an acknowledgment or any form of suggestion that this information forms a prior art that would already be known to a person skilled in the art.